The latest version of the Green Building Council of Australia’s GreenStar rating tool denies its highest ratings to commercial office buildings that cannot demonstrate that they are “fossil fuel free.” That is, that they do not consume natural gas or other fossil fuels on premises, except for backup power generation.
Major institutional property investors have already changed projects mid-construction to design-out gas and are reviewing their portfolios to determine the most cost effective pathways to replace gas plant in existing buildings. Fossil free buildings are likely to attract higher calibre tenants and be quicker to let as more corporates adopt net zero emissions (NZE) targets.
But what's the problem with gas, and what's involved in getting buildings off it?
Little Good About Gas
So-called natural gas is largely methane, a fossil fuel. Exposure to it is bad for our health. Gas stoves and other un-flued gas appliances in homes are a leading cause of childhood asthma, amongst other respiratory conditions.
When methane is vented at wellheads, or leaks from pipes or appliances into the atmosphere (which modern measurement techniques are showing happens far more extensively than had been assumed) it acts as a potent greenhouse gas, heating the planet planet at 86 times the rate of carbon dioxide. Atmospheric concentrations of methane have more than doubled in the last century.
Extracting methane is increasingly expensive and environmentally harmful. As traditional Bass Strait supplies have dwindled, gas exploration companies have turned to horizontal drilling and hydraulic fracturing (“fracking”) to exploit new coal seam gas reserves. These processes are relatively expensive; involve drilling a patchwork of hundreds of wells interconnected with access roads (which destroy bushland, animal habitat and encroach on farmland); produce salt and other toxic waste streams; can irrevocably compromise artesian water supplies; and may contaminate streams and rivers.
Domestic gas prices have also spiked since governments granted rights to extract, liquefy and export fossil methane as LNG, at which point the price Australian consumers pay was linked to global markets. Electricity generated using gas is now significantly more expensive than power from renewable sources, even allowing for the costs of batteries or other forms of storage (that provide continuity for variable solar and wind generation sources).
And now the International Energy Agency has advised that in order to limit warming to no more than 1.5oC and meet the objective of the Paris Climate Accord, no new coal, oil or gas developments can be made. No mines or wells if we are to maintain a safe climate. No new power plants or industrial uses. No new building connections.
So what does that mean for commercial buildings, where heating, hot water and cooking have traditionally been the main uses of gas?
Cooking Without Gas
Electrifying cooking is pretty straightforward once chefs are convinced of the benefits of induction cooking, with its instant heat, fine control, easy to clean surfaces, and efficiency. There are even commercial grade induction units suitable for wok cooking, with large concave elements to provide even heat. The spatial footprint for induction appliances is identical; it’s just a case of getting the power there (more on that in a moment).
Heating and Hot Water
Replacing boilers and other heating and hot water plant may be more challenging. Their electric equivalents, heat pumps, use the same principles as a reverse cycle air conditioning unit, and typically require outdoor and indoor units, potentially creating spatial and even structural challenges in terms of where they can be situated. Council authority approvals are often required if adding external plant due to visual and acoustic impacts to neighbours, unless it can be sited within an existing recessed external plant area. Some buildings use instantaneous gas units for water heating, which have a very small form factor; heat pump systems may require additional bulky and heavy tanks. Pipework may require re-routing. On the other hand, with ever improving coefficient of performance (COP) figures and increasing use of natural refrigerants, they are energy efficient and climate friendly.
Then there’s electricity. As facilities managers will be aware, a commercial building’s power bill has three main parts to it:
- Consumption, charged on a per-kWh basis, often with time of day and/or aggregate consumption charges;
- Maximum demand, charged based on the highest electricity demand in kW during the year; and
- Fixed network and statutory charges.
When building plant is electrified, both consumption and maximum demand patterns will change. While the gas bill will fall, it’s critical to model the impact on electricity over the course of the year. If maximum demand increases, this will both increase those costs, but could also result in the building requiring greater substation capacity and potentially a larger feed from the electricity distributor (if one is readily available given local network constraints). Utilities often pass on substantial costs for submains – this needs to be determined upfront, as it could be prohibitive. Meanwhile, daily and seasonal usage patterns will change and aggregate electricity consumption will increase.
It’s not just the supply to the building that might need to be upgraded. The capacity of the main switchboard, sub-mains cabling running to each floor, distribution boards serving the relevant plant rooms and kitchen areas all need to be reviewed and may require modification.
Fortunately, building electrification may be possible without materially changing maximum demand, and can be cost effective in conjunction with normal plant replacement cycles, particularly when considered holistically as part of a broader services works program. However, it requires careful modelling and effective design to ensure costs don’t go through the roof. Clearly,its requires careful modelling and effective design to ensure costs don’t go through the roof.
One Size Doesn’t Fit All
Whereas most vehicle designs are mass-manufactured and it is often possible to design an electrification retrofit kit that can be rolled out at scale, every commercial building is unique given the original architects’ and engineers’ proclivities, plus differing block sizes and planning constraints. The arrangements and sizing of plant rooms, pipe and cable risers, and of course the various building systems (electrical, mechanical and plumbing) varies considerably from building to building.
Unfortunately, there’s no “one size fits all” solution for removing methane gas uses, and it’s critical to use experienced engineers to ensure electrification upgrades are efficient, cost effective and reliable. And when you’re playing with critical building systems, capable project management is also a must.
Energy Voices is a democratic space presenting the thoughts and opinions of leading Energy & Sustainability writers, their opinions do not necessarily represent those of illuminem.